A Contagious Zeitgeist? The Diffusion of Populism in the European Parliament

A broad array of scholars has studied programmatic spill-over effects from populist to mainstream parties, i.e. whether mainstream parties are adjusting to populist radical right parties’ programmatic orientation. While this is certainly an important question, I argue that it does not fully tap into the concept of a populist zeitgeist. Since populism is increasingly defined in ideational terms, i.e. without any fixed policy profile, scholars should assess populist contagion not only in substantive terms but rather as discursive contagion. Thus, this paper studies the diffusion of populism in the European Parliament from 1999 to 2014 and assesses whether mainstream parties increasingly adapt a populist discourse. Theoretically, I argue that scholars ought to study populist contagion in terms of what populism is: an ideational, thin feature of parties’ rhetoric, rather than a fully-fledged programmatic orientation. The study uses a novel measurement of populist discourse in order to show its development over time and across actors, particularly assessing whether there are time trends and mutual influences between parties.